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Discussion Starter · #1 · (Edited)
I'll start a thread for posting custom exhaust installations. Only post completed custom exhaust work and limit replies to questions about those installations. Try to keep "what if" postings to a minimum so this can serve more as a database than a discussion thread.

I'll start:
My custom exhaust was from the axle back, just forward of the flanged joint.

I used the following, (see first photo attachment):
* Flowmaster 12514310 - 2.5 in & out Flowmaster Hushpower DBX Muffler (9lbs) $150
* Borla 20247 - Borla Standard Exhaust Tip, Single, Weld-on, Stainless, Polished, Slant, 2.5 in. Inlet I.D., 4.5 in. Outlet, 7.75 in. Length (2lbs) $50
* Vibrant Performance 2609 - Vibrant Performance Mandrel-Bent U-J Tubing, 2.50 in. Diameter, 45/180 Degrees, Stainless Steel, 3.5 in. Bend Radius $60

Total of those items weighed together is 14 lbs.

Installation:
Took 1hr 15minutes ($125) at WTB Mufflers of Poway, CA. See second attached photo. As an engineer this installation brings a tear to my eye. Very efficient and clean. You can see they welded a bolt to the rear suspension subframe for another hanger near where the old flanged joint was.
From the third photo you can see they reused both right side hangers and how far the tip protrudes from the bumper.

Results:
Style:
You can see what the single sided exhaust setup looks like from the other pictures. I think the 4.5" inch tip is the perfect size for the bumper cutouts. It sucks to loose the dual exhaust look, but the big single tip makes up for it a bit and this won't be the only car on the road with dual bumper cutouts and single sided exhaust (eg honda accord 4cyl non sport, and dodge challenger V6).

Weight Reduction: Factory Exhaust where I cut it off weighs ~39.5 lbs where it bolts off, is probably ~38lbs. The total weight installed is probably 9lbs muffler, 2lbs tip, 2lbs of pipe used and 1.5 lbs for hangers and welds. so 14.5 lbs total for a total weight savings of 25lbs. WOW! I was only expecting 15lbs. (this is worth almost 2hp/tq by itself), The single exhaust is a big part of this. The lightweight looking dual exhaust corksport unit only saves 8 lbs per their website.

Performance: No dyno baseline and no after dyno baseline sorry. So for a buttdyno, just driving off with the factory muffler still in the trunk (i.e. no weight savings improvement) this feels like a standard passenger car muffler restriction removal. What I mean by that is the skyactiv muffler does not somehow flow rediculously well, I am seeing the same improvements as on previous Nissan 4cylinders:
The engine no longer feels soft. I would not say throttle response time is improved, but from the time the motor starts reacting to the throttle until full thrust is acheived has gone to zero.
Just pulling out into traffic normally the car accelerated faster than normal, and cruising down the street it seemed to take a smidge less throttle than before, so part throttle performance is significantly better at sub 4k RPMs.
Full throttle feels faster all the way through the powerband. This is probably a 7-10 hp/tq gain not a 3-5hp/tq gain.

Mileage: If the correlation to my previous Nissans holds I should be able to get a 1-2mpg improvement in city driving, and something more than zero on the highway, but with the loss of the diffuser function of the stock muffler I'm not so sure there will be any gain at all.

Sound: The tone, the character of the sound is very fitting for the 6. My disagrees with me though, she said "you took such an elegantly looking car and made it sound like a Mustang." LoL It is crazy deep with very meaty, well defined exhaust pulses (NEVER farty) all the way through the rev range and very little else, like listening to your favorite high end subwoofer during the Matrix lobby scene. For volume this is where it get's interesting. At idle (650rpm) it's bone stock completely silent. Cruising you can here the same meaty character coming into the cabin but still pretty darn quiet. At WOT the engine actually starts to drown out the exhaust above 4k. BUT this particular exhaust setup has a real prominent resonant frequency at about the 1800-2k range. It is probably twice the perceived volume of the other RPM ranges, which is different than other flowmasters I have had where the drone is present accross all low and mid frequencies regardless of rpm. Because it is so specific of a frequency I believe the proper thing to fix it would be a Heimholtz J pipe resonator. We'll see if it bother's me enough to try to fix it.

Final verdict: Awesome, no regrets. Major weight reduction, nice quality tone, doesn't look bad, much better engine strength and performance, and ultimately fuel economy. This car is much more satisfying to me to drive now.
 

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Sort of looks like the magnaflow setup that was on the Mazda 6 pacecar.

IMHO opinion I think the single setup looks out of place. Maybe it is because I am used to seeing the dual setup on the 6 but I definitely like the dual setup better.

Any sound clips?
 

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I'm getting 23mpg on my 6 since I bought it because all it ever sees is stoplights and hills. Everybody's objectives are different. This setup fits my objectives perfectly.

Separately, to the other poster, no I won't be posting sound clips for a couple reasons, I don't have access to any decent recording gear that would accurately reflect the deep tone, which is the prominent feature of this setup so there is little point as a primary reason.

And yes the dual setup does look better, of course, but not so much better to justify the extra cost and weight for me (my opinion only). There is another silver touring in my work parking lot right now, and it's tips are looking way too small after staring at my setup for a while. So in short my set up looks sportier, but the stock setup looks classier, neither are perfect.
 

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I wonder if we could get the sound clips from those who put the race and other cat backs on here so we do have to search for them...
 

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Discussion Starter · #8 · (Edited)
From a factory muffler to a straight through design (bullet in fact if you're oh so familiar with all options and possibilities for improving power). There are conditions when you can gain power from such a modification. Is the 6 one of them? I personally doubt it, but you can not claim that across all cars available today!
Hey, as mentioned before I've done a chambered flowmaster swap on a 1992 Nissan Stanza (40 series), 1994 Nissan Altima (60 series Delta flow), and also a roadstersport muffler on a 2001 miata, and some no-name brand performance catback on a 1990 325i. All those mods were performed when the vehicles had about 90-100k miles so clogging/rusting out of the stock exhaust could have even been a contributor to the performance improvement of the muffler swap.

The seat of the pants acceleration improvement for the 6 with this mod is right up there with the improvement seen with my 1992 nissan stanza and the 325i (which responded awesome to mods: 14hp for just extrude honing an intake manifold!). The miata was almost no improvement, just a lot of noise.

So to be clear, with my experience base of exhaust mods per above, my conclusion is the stock 2014 Mazda6 muffler is restrictive, and going to a straight through muffler will give a noticeable improvement in acceleration typical of most cars from the last 20 years, which as a corksport exhaust swapper said feels like the difference between having the AC on and an extra passenger which if you crunch the numbers would be over a 10hp change.
 

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I would just have to feel it or see #'s on it to believe it in this case solar. Mazda's claim is to get exhaust gasses and thus heat out of the combustion chamber as quickly as possible. The header design makes this obvious, and restrictions even as far back as the muffler would cause a delay there rather quickly slowly the escape from the header by a back up of the slower moving gasses at the tail end. Delay = more heat build-up in the chamber, more potential for knock/pre-detonation. SOTP is hard to quantify though, as with one passenger to me there isn't a notable difference in performace with the 6. Now with my whole family and a months worth of groceries.. the drive home is a nightmare LOL.... now jump in my formula after driving the 6.. that's a SOTP you can tell! LOL. (from under 200 up to 400HP in similarly weighted car haha)
 

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I will have my dyno results posted tomorrow on the Dyno thread. I unfortunately will not have a baseline. I already have the Corksport SRI and exhaust installed. Hopefully someone will find it in their wallet to blow $100 to dyno a stock car.
 
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I will have my dyno results posted tomorrow on the Dyno thread. I unfortunately will not have a baseline. I already have the Corksport SRI and exhaust installed. Hopefully someone will find it in their wallet to blow $100 to dyno a stock car.
Looking forward to your results! Thanks for taking one for the team. :D

Any CEL's so far with the SRI? How many miles on it approx? Thanks in advance~
 

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Looking forward to your results! Thanks for taking one for the team. :D

Any CEL's so far with the SRI? How many miles on it approx? Thanks in advance~
No CEL. I have a pre March 2013, so the MAF is good with it. I have about 10000 on the exhaust and 3000 with the intake. I put the intake on right before a 2200 mile road trip to Daytona last month. The exhaust has been on since August.

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I will have my dyno results posted tomorrow on the Dyno thread. I unfortunately will not have a baseline. I already have the Corksport SRI and exhaust installed. Hopefully someone will find it in their wallet to blow $100 to dyno a stock car.
crf50racer,

Now granted I am not aware of the gains available on smaller displacement engines, however if you look at an engine like an air pump, the more efficient you can make it, the more power you will have. Intakes and exhaust from the factory are trying to be many things and we all know how that story goes, jack of all trades, master of none :)

I too apologize for hijacking this thread. I look forward to your dyno #'s.

Question, are the build dates causing problems for the intakes?

Thank you,

Chris
 

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crf50racer,

Now granted I am not aware of the gains available on smaller displacement engines, however if you look at an engine like an air pump, the more efficient you can make it, the more power you will have. Intakes and exhaust from the factory are trying to be many things and we all know how that story goes, jack of all trades, master of none :)

I too apologize for hijacking this thread. I look forward to your dyno #'s.

Question, are the build dates causing problems for the intakes?

Thank you,

Chris
Yes. If you look on CorkSport's website, you have a choice of builds. The MAF was changed in March '13 because of some issue with them throwing CEL's. I had to drive a thousand miles to Daytona last year with the damn CEL glaring at me. In the pre March cars, Mazda just did a software update. Post March they changed the MAF, and so the intakes require a larger intake. I'm still proud to be one of the first buyers of this car, even with the headaches of an all new model.

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Yes I did mention it actually:

"Mileage: If the correlation to my previous Nissans holds I should be able to get a 1-2mpg improvement in city driving, and something more than zero on the highway, but with the loss of the diffuser function of the stock muffler I'm not so sure there will be any gain at all."
I absolutely stand corrected! And absolutely have not problem with that


Regarding the rest of your comments I'll keep having my fun optimism and let the dyno runs that will keep trickling in on the other threads be my defense.
fair enough, and nicely worded position!
 
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Hey, as mentioned before I've done a chambered flowmaster swap All those mods were performed when the vehicles had about 90-100k miles so clogging/rusting out of the stock exhaust could have even been a contributor to the performance improvement of the muffler swap.
Thank you. Very properly noted, and an actual contribution to a discussion. How many more points like the above are omitted, disregarded, and not included in a discussion?

As to your comment on the restriction of Mazda6's OEM muffler, yes, of course any shape other than a straight pipe is by a definition more restrictive than a straight pipe. But this a spurious route. All of the evidence seems to point in the direction that modern OEM mufflers, if anything, have a spare capacity for a flow through.

It's the emission stuff that is the main restricting aspect. Only after emission link is resolved, will messing with muffler provide any significant change. Until then, doing something to a muffler, is like taking a flu medicine against the flu, while having an acute case of gangrene - it wont improve an overall condition
 

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Discussion Starter · #17 · (Edited)
ACTUALLY this thread was supposed to be about people posting their custom exhaust setup and their results, and now it's beyond repair.

I've honestly had about enough of this forums armchair Mazda design engineers telling people their testimonials and dyno runs can't possibly be true, ruining the threads.
 

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ACTUALLY this thread was supposed to be about people posting their custom exhaust setup and their results, and now it's beyond repair.

I've honestly had about enough of this forums armchair Mazda design engineers telling people their testimonials and dyno runs can't possibly be true, ruining the threads.

I'm sorry for that. I got sucked in by TS.

Chris
 
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